For guys competing in unlimited-displacement race classes like IHRA Pro Stock or NHRA Top Sportsman, there really is no replacement for displacement. In these niche worlds with no limits, Sonny's Racing has long been the mountain motor leader. Founder Sonny Leonard has specialized in big, big-block Chevy-based motors for more than 41 years, building ever larger and more radical combos that in their most advanced incarnations bare only a superficial resemblance to Chevy's original Rat.

And by "big" we don't just mean a wussy 496, a puny 540, or even a wimpy 572. No, we're talking giant, megafauna, Pleistocene-epoch massiveness here-you know, 1,000,000 years BC big, 1,000-pound saber-toothed tiger big, 10-foot-tall beaver big. Sonny's motors start out around 611 ci and have grown ever larger, with standard production mills now offered as large as 940 ci. Getting there has meant increasingly taller, wider, and longer blocks. In turn, the heads have evolved to keep up with the larger displacements and ever-increasing bore spacing, with Sonny's top-line offerings sporting straight-shot hemispherical chambers with nearly 3-inch intake valves.

Now Sonny has upped the ante once again. By the time you read this, CEO Racing's Craig Olson (Camaro Island, Washington) should have taken delivery of Sonny's latest effort, a 1,005.8ci (5.220-inch bore x 5.875-inch stroke) engine that normally aspirated on 112-octane race gas running electronic fuel injection (EFI) pounds out more than 2,150 hp at 8,000 rpm, with a tire-melting 1,500-plus lb-ft of torque at 6,200 rpm.

Everything from the overgrown billet aluminum block to Sonny's trick hemispherical heads is a clean-sheet-of-paper design. Only the main and rod journal sizes and Chevy bellhousing bolt pattern remain from the original GM configuration. All internals-including the foot-long, 5/8-inch pushrods, the 8-inch rods, and the 1.3-inch-lift cam-are made to order. The first prototype built for Olson cost $125,000, but expect future full-race versions to be a more reasonable $110,000.

A milder $95,000 street version is also in the works. It will have a street roller cam, 8 instead of 16 injectors, smaller throttle-bodies, and a full water jacket. Designed to run on 92-octane, Sonny figures it oughta make a "measly" 1,650 hp at 7,000 rpm, with "only" 1,400 lb-ft at 5,700 normally aspirated.

But get out your shoehorn: The 1,005 is 34 inches at its widest point (the valve covers' outer edges). From crank centerline to the top of the valve covers and EFI throttle-body it measures, respectively, 20 and 26.5 inches. It extends 32 inches from the flywheel flange to the crank bolt (1.400 inches more than a stock big-block Chevy). Old Impala, anyone?

Is 1,005 the final evolution or will even more massive motors follow? Only Sonny knows, and he's playing his cards close to the 1,005's 12 -inch-tall block deck. Meanwhile, let's see what makes Sonny's beast tick.

"On gas, a hemi head is worth 2 to 3 percent power over a wedge; maybe 10 percent more in Top Fuel." -Sonny Leonard